Internal Combustion Engine Valve Train Device

ABSTRACT

An internal combustion engine valve train device of a motor vehicle, includes at least one exhaust valve actuating unit and at least one intake valve actuating unit, and an operating mode switching unit that is provided for switching the exhaust valve actuating unit into an exhaust gas recirculation mode in order to adjust an internal exhaust gas recirculation. The operating mode switching unit is provided for also switching the intake valve actuating unit into an exhaust gas recirculation mode in order to adjust an internal exhaust gas recirculation.

BACKGROUND AND SUMMARY OF THE INVENTION

Exemplary embodiments of the invention relate to an internal combustion engine valve train device.

German patent document DE 10 2010 051 130 A1 discloses an internal combustion engine valve train device of a motor vehicle having at least one exhaust valve actuating unit and at least one intake valve actuating unit, and an operating mode switching unit that is provided for switching the exhaust valve actuating unit into an exhaust gas recirculation mode in order to adjust an internal exhaust gas recirculation.

Exemplary embodiments of the present invention are directed to reducing fuel consumption of a motor vehicle which has the internal combustion engine valve train device.

Exemplary embodiments of the present invention are directed to an internal combustion engine valve train device of a motor vehicle, having at least one exhaust valve actuating unit and at least one intake valve actuating unit, and an operating mode switching unit that is provided for switching the exhaust valve actuating unit into an exhaust gas recirculation mode in order to adjust an internal exhaust gas recirculation.

In accordance with the invention the operating mode switching unit is provided for additionally switching the intake valve actuating unit into an exhaust gas recirculation mode in order to adjust an internal exhaust gas recirculation. In this way, an intake valve actuation and an exhaust valve actuation may be adapted specifically to the exhaust gas recirculation, as the result of which a particularly advantageous internal exhaust gas recirculation may be achieved. A constant exhaust gas recirculation quantity in the exhaust gas recirculation mode may be ensured, so that pollutant emissions may be reduced. In addition, the drive power for the intake valve actuation and/or the drive power for the exhaust valve actuation in the exhaust gas recirculation mode may be reduced, so that the efficiency may be increased. The fuel consumption of a motor vehicle having the internal combustion engine valve train device may be reduced in this way. An “exhaust gas recirculation quantity” should be understood to mean an exhaust gas quantity that is resupplied to a cylinder by the internal exhaust gas recirculation for a subsequent combustion operation. The exhaust valve actuating unit is preferably operable at least in a normal mode and an exhaust gas recirculation mode. The intake valve actuating unit is preferably operable at least in a normal mode and an exhaust gas recirculation mode. An “operating mode switching unit” should be understood to mean a unit that is provided for switching between at least two different operating modes, preferably at least between a normal mode and an exhaust gas recirculation mode. The operating mode switching unit preferably switches the exhaust valve actuating unit and/or the intake valve actuating unit in order to set the corresponding operating mode. The operating mode switching unit is advantageously provided for switching a valve actuation characteristic of the exhaust valve actuating unit and/or of the intake valve actuating unit in discrete steps. The operating mode switching unit is particularly preferably provided for functionally bringing at least one intake valve in contact with one of at least two cam tracks of the intake valve actuating unit, and/or for functionally bringing at least one exhaust valve in contact with one of at least two cam tracks of the exhaust valve actuating unit. An “internal exhaust gas recirculation” is understood in particular to mean an exhaust gas recirculation in which exhaust gas from an exhaust tract is directly resupplied to a cylinder. The term “provided” is understood in particular to mean specially programmed, equipped, designed, and/or situated.

It is further proposed that the intake valve actuating unit has at least one intake cam which includes at least one first cam track for a normal mode and a second cam track for the exhaust gas recirculation mode. The exhaust gas recirculation mode may thus be set in a particularly advantageous manner. The exhaust valve actuating unit preferably has at least one exhaust cam which includes at least one first cam track for the normal mode and a second cam track for the exhaust gas recirculation mode. An “intake cam” should be understood to mean an element that is provided for actuating at least one intake valve, the element for actuating the intake valve preferably being provided for directly or indirectly acting on the intake valve with at least one lift. An “exhaust cam” should be understood to mean an element that is provided for actuating at least one exhaust valve, the element for actuating the exhaust valve preferably being provided for directly or indirectly acting on the exhaust valve with at least one lift. For switching the operating modes, the at least one intake cam is situated on an intake cam base shaft so as to be axially displaceable but rotationally fixed. For switching the operating modes, the at least one exhaust cam is situated on an exhaust cam base shaft so as to be axially displaceable but rotationally fixed. A “cam track” should be understood to mean a portion of a cam provided for directly actuating a gas exchange valve and/or for picking up by means of a cam follower for actuating the gas exchange valve. A cam track preferably has a gas valve actuation curve. The cam track is preferably designed as an area extending over the periphery of the intake cam or of the exhaust cam, and which forms the gas valve actuation curve for actuating the corresponding gas exchange valve and/or which defines the actuation by providing at least one valve actuation parameter. The gas exchange valve is advantageously designed as an intake valve or as an exhaust valve. The gas valve actuation curve is preferably designed as an intake valve actuation curve or as an exhaust valve actuation curve.

In addition, the second cam track of the at least one intake cam differs from the first cam track of the at least one intake cam by at least one valve actuation parameter, as the result of which the intake valve actuation may be specifically adapted to the internal exhaust gas recirculation. A “valve actuation parameter” should be understood to mean a parameter provided by a configuration of the cam track and which defines the actuation of the corresponding gas exchange valve. The valve actuation parameter is preferably defined and/or described by the gas valve actuation curve.

In particular, it is advantageous when the second cam track of the at least one intake cam is provided for setting an intake valve opening phase at least essentially outside an exhaust valve opening phase. For an at least essentially closed intake valve, an exhaust gas may thus be drawn back in, as the result of which the exhaust gas recirculation quantity may be precisely metered. The second cam track of the at least one intake cam is preferably provided for keeping at least one intake valve at least largely closed during an actuation of at least one exhaust valve. The term “setting an intake valve opening phase outside an exhaust valve opening phase” should be understood to mean that a shared opening phase of the intake valve and of the exhaust valve, and/or an overlap area of an intake valve actuation curve and an exhaust valve actuation curve, preferably along a crankshaft angle in degrees, is absent. The term “essentially” should be understood to mean that within a working cycle, a shared opening phase has a duration of a maximum of 30 degrees crankshaft, advantageously a maximum of 15 degrees crankshaft angle, and particularly advantageously a maximum of 5 degrees crankshaft angle. A overlap area of the intake valve actuation curve and of the exhaust valve actuation curve for an intake opening phase for an intake opening phase that is set essentially outside the exhaust opening phase is a maximum of 30 degrees crankshaft angle, advantageously a maximum of 15 degrees crankshaft angle, and particularly advantageously a maximum of 5 degrees crankshaft angle. A “working cycle” should be understood to mean the smallest possible recurring circular process that is divided into at least two subdivided cycles of a piston movement in a cylinder. A cycle is preferably defined by the piston movement in one direction from a standstill until the next standstill, i.e., from one dead center to another dead center. A cycle advantageously corresponds to one-half revolution of a crankshaft, i.e., preferably 180 degrees crankshaft angle. A working cycle advantageously corresponds to two revolutions of the crankshaft, i.e., preferably 720 degrees crankshaft angle. The intake valve opening phase and the exhaust valve opening phase are preferably situated with respect to one another at least essentially free of overlap, in particular along the crankshaft angle in degrees.

Furthermore, it is advantageous when the second cam track of the at least one intake cam provides a valve actuation parameter designed as the lift height and which differs from a valve actuation parameter of the first cam track of the at least one intake cam, designed as the lift height. The intake valve actuation may be adapted in a particularly advantageous manner in this way. The term “valve actuation parameter designed as the lift height” should be understood to mean a valve actuation parameter which is defined by a level at a high point of the gas valve actuation curve.

In addition, it is advantageous when the valve actuation parameter of the second cam track of the at least one intake cam, designed as the lift height, is smaller than the valve actuation parameter of the first cam track of the at least one intake cam, designed as the lift height, as the result of which the drive power for the intake valve actuation in the exhaust gas recirculation mode may be reduced using a simple design.

In another embodiment according to the invention, the second cam track of the at least one intake cam provides a valve actuation parameter designed as the opening duration and which differs from a valve actuation parameter of the first cam track of the at least one intake cam, designed as the opening duration. The intake valve actuation in the exhaust gas recirculation mode may be optimized in this way. The term “valve actuation parameter designed as the opening duration” should be understood to mean a valve actuation parameter defined by a crankshaft angle range in degrees, in which a lift of the corresponding gas valve actuation curve is greater than zero, preferably within a working cycle. The valve actuation parameter designed as the opening duration preferably defines a crankshaft angle range in degrees, in which the at least one intake valve or the at least one exhaust valve is open, preferably within a working cycle.

Furthermore, in accordance with exemplary embodiments of the invention the actuation parameter of the second cam track of the at least one intake cam, designed as the opening duration, is shorter than the valve actuation parameter of the first cam track of the at least one intake cam, designed as the opening duration, as the result of which the drive power for the intake valve actuation in the exhaust gas recirculation mode may be further reduced in a particularly simple manner. In the present context, the term “shorter” should be understood to mean a shorter opening phase. The valve actuation parameter, which is provided by the second cam track of the at least one intake cam and is shorter than the opening duration, is preferably defined by a gas valve actuation curve that is narrower than the gas valve actuation curve which defines the actuation parameter of the at least one intake cam, designed as the opening duration.

In addition, the exhaust valve actuating unit has at least one exhaust cam, with at least one cam track for the exhaust gas recirculation mode that provides at least two valve actuation parameters designed as the lift height, and the valve actuation parameter of the second cam track of the at least one intake cam, designed as the lift height, differs from both valve actuation parameters of the cam track of the at least one exhaust cam, designed as the lift height. In this way, the intake valve actuation in the exhaust gas recirculation mode may be adapted to the exhaust valve actuation in the exhaust gas recirculation mode in a particularly advantageous manner.

In particular, it is advantageous when the valve actuation parameter of the second cam track of the at least one intake cam, designed as the lift height, is smaller than at least one of the two valve actuation parameters of the cam track of the at least one exhaust cam, designed as the lift height, as the result of which a particularly advantageous internal exhaust gas recirculation may be achieved. The valve actuation parameter of the second cam track of the at least one intake cam, designed as the lift height, is preferably larger than one of the two valve actuation parameters of the cam track of the at least one exhaust cam, designed as the lift height.

The operating mode switching unit particularly preferably has at least one switch gate provided for converting a rotary movement into an axial movement, at least for switching the exhaust gas recirculation mode. As a result, particularly advantageous switching between the normal mode and the exhaust gas recirculation mode may be achieved. A “switch gate” should be understood to mean a unit having at least one gate track provided for converting a rotary movement into an axial adjusting force. A “gate track” should be understood mean a track for forced guidance of a gate engagement element at least on one side, preferably on both sides. The gate track is preferably designed in the form of a web, in the form of a slot, and/or in the form of a groove. A “gate engagement element” should be understood to mean an element which in at least one operating state at least partially engages with the switch gate and/or at least partially surrounds the switch gate and thus is preferably in operative connection with the switch gate, as the result of which the element is forcibly guided by the switch gate. The gate engagement element is preferably designed in the form of a shifting shoe which surrounds the web, in the form of a pin which engages in the slot, and/or in the form of a pin which is guided in the groove. The switch gate is preferably designed either as a separate element connected to at least one intake cam or to at least one exhaust cam in a rotationally and displaceably fixed manner, or as one piece with the intake cam or with the least one exhaust cam. The switch gate is advantageously provided for converting a rotary movement of the at least one intake cam into an axial movement of the at least one intake cam, and/or for converting a rotary movement of the at least one exhaust cam into an axial movement of the at least one exhaust cam, at least for switching the exhaust gas recirculation mode.

Additionally, exemplary embodiments of the invention are directed to a method for adjusting an internal exhaust gas recirculation of an internal combustion engine valve train device of a motor vehicle, in particular an internal combustion engine valve train device according to the invention, in which an exhaust valve actuating unit and also an intake valve actuating unit are switched into an exhaust gas recirculation mode in order to adjust the internal exhaust gas recirculation.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

Further advantages result from the following description of the drawings. The drawings illustrate one exemplary embodiment of the invention. The drawings, the description, and the claims contain numerous features in combination. Those skilled in the art will also advantageously consider the features individually and combine them into further meaningful combinations.

The figures show the following:

FIG. 1 shows a portion of an internal combustion engine valve train device, having an exhaust valve actuating unit and an intake valve actuating unit, and an operating mode switching unit which switches the exhaust valve actuating unit and the intake valve actuating unit into an exhaust gas recirculation mode in order to adjust an internal exhaust gas recirculation; and

FIG. 2 shows an exhaust valve actuation curve of the exhaust valve actuating unit which is switched in the exhaust gas recirculation mode, and an intake valve actuation curve of the intake valve actuating unit which is switched in the exhaust gas recirculation mode.

DETAILED DESCRIPTION

FIG. 1 shows an internal combustion engine valve train device of a motor vehicle. For providing a drive torque, the motor vehicle has an internal combustion engine, not illustrated in greater detail, having exhaust valves and intake valves that are actuated by the internal combustion engine valve train device during operation of the internal combustion engine. The internal combustion engine valve train device has an exhaust valve actuating unit 10 for actuating the exhaust valves, and has an intake valve actuating unit 11 for actuating the intake valves. For switching between two operating modes of the internal combustion engine, the internal combustion engine valve train device has an operating mode switching unit 12, which switches the exhaust valve actuating unit 10 as well as the intake valve actuating unit 11 in order to set the appropriate operating mode. In this exemplary embodiment, the internal combustion engine has two operating modes, one operating mode being designed as a normal mode and the other being designed as an exhaust gas recirculation mode. The operating mode switching unit 12 switches the exhaust gas recirculation mode in order to adjust an internal exhaust gas recirculation. In principle, the internal combustion engine may also have other operating modes. The motor vehicle is designed as a passenger vehicle.

For setting the normal mode, the exhaust valve actuating unit 10 and the intake valve actuating unit 11 each have a normal mode. For setting the exhaust gas recirculation mode, the exhaust valve actuating unit 10 and the intake valve actuating unit 11 each have an exhaust gas recirculation mode. The exhaust valve actuating unit 10 and the intake valve actuating unit 11 are each operable in a first operating mode and in a second operating mode. The normal mode and the exhaust gas recirculation mode of the exhaust valve actuating unit 10 differ in the exhaust valve actuation curves. The normal mode and the exhaust gas recirculation mode of the intake valve actuating unit 11 differ in the intake valve actuation curves.

For adjusting the internal exhaust gas recirculation, the operating mode switching unit 12 switches the exhaust valve actuating unit 10 and the intake valve actuating unit 11 into the exhaust gas recirculation mode, starting from the normal mode. For setting a normal mode, i.e., an operation without internal exhaust gas recirculation, the operating mode switching unit 12 switches the exhaust valve actuating unit 10 and the intake valve actuating unit 11 into the normal mode, starting from the exhaust gas recirculation mode. The operating mode switching unit 12 switches the exhaust valve actuating unit 10 and the intake valve actuating unit 11 simultaneously into the appropriate operating mode. In principle, the operating mode switching unit 12, the exhaust valve actuating unit 10, and the intake valve actuating unit 11 may switch into the appropriate operating mode in a staggered manner.

The intake valve actuating unit 11 has multiple intake cams for actuating the intake valves, only the intake cams 13, 14 being illustrated for the sake of clarity. For providing the normal mode and the exhaust gas recirculation mode, the intake cams 13, 14 each have a first cam track 17 for the normal mode and a second cam track 18 for the exhaust gas recirculation mode. The first cam track 17 of the intake cams 13, 14 has an intake valve actuation curve for the normal mode, and the second cam track 18 of the intake cams 13, 14 has an intake valve actuation curve 37 for the exhaust gas recirculation mode. The intake valve actuation curve for the normal mode and the intake valve actuation curve 37 for the exhaust gas recirculation mode differ from one another. The intake valve actuation curve 37 for the exhaust gas recirculation mode has a lift that differs from a lift of the intake valve actuation curve for the normal mode. The second cam track 18 of the intake cams 13, 14 differs from the first cam track 17 of the corresponding intake cams 13, 14 in two valve actuation parameters 19, 20.

The second cam track 18 of the intake cams 13, 14 provides a valve actuation parameter 19 designed as the lift height, and which differs from a valve actuation parameter of the first cam track 17 of the intake cams 13, 14, designed as the lift height. The actuation parameter 19 of the second cam track 18 of the intake cams 13, 14, designed as the lift height valve, is smaller than the valve actuation parameter of the first cam track 17 of the intake cams 13, 14, designed as the lift height. The lift of the intake valve actuation curve 37 for the exhaust gas recirculation mode is smaller than the lift of the intake valve actuation curve for the normal mode. The valve actuation parameter of the first cam track 17 of the intake cams 13, 14, designed as the lift height, is designed as a maximum lift of the intake valve actuation curve for the normal mode. The valve actuation parameter 19 of the second cam track 18 of the intake cams 13, 14, designed as the lift height, is designed as a maximum lift of the intake valve actuation curve 37 for the exhaust gas recirculation mode.

The second cam track 18 of the intake cams 13, 14 also provides a valve actuation parameter 20 designed as the opening duration and which differs from a valve actuation parameter of the first cam track 17 of the intake cams 13, 14, designed as the opening duration. The valve actuation parameter 20 of the second cam track 18 of the intake cams 13, 14, designed as the opening duration, is shorter than the valve actuation parameter of the first cam track 17 of the intake cams 13, 14, designed as the opening duration. The lift of the intake valve actuation curve 37 for the exhaust gas recirculation mode is narrower than the lift of the intake valve actuation curve for the normal mode. The valve actuation parameter 20 of the second cam track 18 of the intake cams 13, 14, designed as the opening duration, sets an intake valve opening phase 21 of the intake valves that is shorter than an intake valve opening phase of the intake valves set by the valve actuation parameter of the first cam track 17 of the intake cams 13, 14, designed as the opening duration.

The intake valve actuating unit 11 has an intake cam element 38 for accommodating the intake cams 13, 14. The intake cams 13, 14 are each situated on the intake cam element 38 in a rotationally and displaceably fixed manner. For accommodating the intake cam element 38, the intake valve actuating unit 11 has an intake cam base shaft 39 which is in drive connection with a crankshaft of the internal combustion engine. The intake cam element 38 is situated on the intake cam base shaft 39 so as to be rotationally fixed but axially displaceable. The intake valve actuating unit 11 is designed as an intake camshaft unit.

For actuating the exhaust valves, the exhaust valve actuating unit 10 has multiple exhaust cams, only the exhaust cams 24, 25 being illustrated for the sake of clarity. For providing the normal mode and the exhaust gas recirculation mode, the exhaust cams 24, 25 each have a first cam track 40 for the normal mode and a second cam track 28 for the exhaust gas recirculation mode. The first cam track 40 of the exhaust cams 24, 25 has an exhaust valve actuation curve for the normal mode, and the second cam track 28 of the exhaust cam 24, 25 has an exhaust valve actuation curve 41 for the exhaust gas recirculation mode. The exhaust valve actuation curve for the normal mode and the exhaust valve actuation curve 41 for the exhaust gas recirculation mode differ from one another. The exhaust valve actuation curve 41 for the exhaust gas recirculation mode has a lift that differs from a lift of the exhaust valve actuation curve for the normal mode. The second cam track 28 of the exhaust cams 24, 25 differs from the first cam track 40 in the number of lifts.

The first cam track 40 of the exhaust cams 24, 25 provides a single valve actuation parameter designed as the lift height. The exhaust valve actuation curve for the normal mode has a single lift. The second cam track 28 of the exhaust cams 24, 25 provides two valve actuation parameters 29, 30 designed as the lift height. The valve actuation parameters 29, 30 of the second cam track 28 of the exhaust cams 24, 25, designed as the lift height, are different from one another. The valve actuation parameter 29 of the second cam track 28 of the exhaust cams 24, 25, designed as the lift height, is larger than the valve actuation parameter 30 of the second cam track 28 of the exhaust cams 24, 25, designed as the lift height. The valve actuation parameter 30 of the second cam track 28 of the exhaust cams 24, 25, designed as the lift height, is provided for the internal exhaust gas recirculation, and opens the corresponding exhaust valve during a downward movement of a piston, the corresponding intake valve being largely closed due to the intake valve actuation curve 37. The exhaust valve actuation curve 41 for the exhaust gas recirculation mode has a double lift.

The valve actuation parameters 29, 30 of the second cam track 28 of the exhaust cams 24, 25, designed as the lift height, both differ from the valve actuation parameter of the first cam track 40 of the exhaust cams 24, 25, designed as the lift height. The valve actuation parameters 29, 30 of the second cam track 28 of the exhaust cams 24, 25, designed as the lift height, are both smaller than the valve actuation parameter of the first cam track 40 of the exhaust cams 24, 25, designed as the lift height. The lift of the exhaust valve actuation curve 41 for the exhaust gas recirculation mode is smaller than the lift of the exhaust valve actuation curve for the normal mode.

The second cam track 28 of the exhaust cams 24, 25 also provides a valve actuation parameter designed as the opening duration and which differs from a valve actuation parameter of the first cam track 40 of the exhaust cams 24, 25, designed as the opening duration. The valve actuation parameter of the second cam track 28 of the exhaust cams 24, 25, designed as the opening duration, is longer than the valve actuation parameter of the first cam track 40 of the exhaust cams 24, 25, designed as the opening duration. The valve actuation parameter of the second cam track 28 of the exhaust cams 24, 25, designed as the opening duration, sets two exhaust valve opening phases 22, 23 of the exhaust valves, which together are longer than a single exhaust valve opening phase of the exhaust valves which is set by the valve actuation parameter of the first cam track 40 of the exhaust cams 24, 25, designed as the opening duration.

The valve actuation parameter of the first cam track 40 of the exhaust cams 24, 25, designed as the lift height, is designed as a maximum lift of the exhaust valve actuation curve for the normal mode. The valve actuation parameters 29, 30 of the second cam track 28 of the exhaust cams 24, 25, designed as the lift height, are each designed as a maximum lift of the exhaust valve actuation curve 41 for the exhaust gas recirculation mode.

The exhaust valve actuation curve 41 has a zero lift 45, with respect to a crankshaft angle 44 in degrees, between the maximum lifts of the exhaust valve actuation curve 41. The zero lift 45 is situated with respect to the crankshaft angle 44 in degrees in such a way that a collision between the piston of the internal combustion engine and the corresponding exhaust valve is prevented. The zero lift 45 is situated, with respect to the crankshaft angle 44 in degrees, in the region of an ignition top dead center. A lift of the piston is represented by a piston lift curve 46. The smaller maximum lift of the exhaust valve actuation curve 41 for the exhaust gas recirculation mode is situated with respect to the crankshaft angle 44 in degrees, and within a working cycle, between the larger maximum lift of the exhaust valve actuation curve 41 for the exhaust gas recirculation mode and the maximum lift of the intake valve actuation curve 37 for the exhaust gas recirculation mode. Within the working cycle, the maximum lift of the intake valve actuation curve 37 for the exhaust gas recirculation mode is situated, with respect to the crankshaft angle 44 in degrees, after the two maximum lifts of the exhaust valve actuation curve 41 for the exhaust gas recirculation mode. In principle, instead of a zero lift 45, the exhaust valve actuation curve 41 may have a local minimum lift, with respect to the crankshaft angle 44 in degrees, between the maximum lifts of the exhaust valve actuation curve 41.

The exhaust valve actuating unit 10 has an exhaust cam element 42 for accommodating the exhaust cams 24, 25. The exhaust cams 24, 25 are each situated on the exhaust cam element 42 in a rotationally and displaceably fixed manner. For accommodating the exhaust cam element 42, the exhaust valve actuating unit 10 has an exhaust cam base shaft 43, which is in drive connection with the crankshaft of the internal combustion engine. The exhaust cam element 42 is situated on the exhaust cam base shaft 43 so as to be rotationally fixed but axially displaceable. The exhaust valve actuating unit 10 is designed as an exhaust camshaft unit.

The intake valve actuation curve 37 for the exhaust gas recirculation mode and the exhaust valve actuation curve 41 for the exhaust gas recirculation mode differ from one another. The intake valve actuation curve 37 for the exhaust gas recirculation mode has a lift that differs from the lift of the exhaust valve actuation curve 41 for the exhaust gas recirculation mode.

The valve actuation parameter 19 of the second cam track 18 of the intake cams 13, 14, designed as the lift height, differs from both valve actuation parameters 29, 30 of the second cam track 28 of the exhaust cams 24, 25, designed as the lift height. The valve actuation parameter 19 of the second cam track 18 of the intake cams 13, 14, designed as the lift height, is smaller than one of the two valve actuation parameters 29, 30 of the second cam track 28 of the exhaust cams 24, 25, designed as the lift height. The valve actuation parameter 19 of the second cam track 18 of the intake cams 13, 14, designed as the lift height, is smaller than the valve actuation parameter 29 of the second cam track 28 of the exhaust cams 24, 25, designed as the lift height, and larger than the valve actuation parameter 29 of the second cam track 28 of the exhaust cams 24, 25, designed as the lift height.

The second cam track 18 of the intake cams 13, 14 sets the intake valve opening phase 21 essentially outside the exhaust valve opening phases 22, 23. The intake valve actuation curve 37 is designed in such a way that the intake valve opening phase 21 is set essentially outside the exhaust valve opening phases 22, 23. The intake valves are thus largely closed during an actuation of the exhaust valves. The intake valves are therefore largely closed during a return of an exhaust gas recirculation quantity. An intake valve opening point 47 is situated within the exhaust valve opening phase 23. An intake valve closing point 48 is situated outside both exhaust valve opening phases 22, 23. The corresponding intake valves are opened within the intake valve opening phase 21, and the corresponding exhaust valves are opened within the exhaust valve opening phases 22, 23. The exhaust valve opening phase 23 is provided for the internal exhaust gas recirculation, and sets the exhaust gas recirculation quantity in the exhaust gas recirculation mode. The exhaust valve opening phase 23 is designed as an exhaust gas recirculation opening phase.

The intake valve actuation curve 37 for the exhaust gas recirculation mode and the exhaust valve actuation curve 41 for the exhaust gas recirculation mode have only a single overlap area 49 within a working cycle, and thus within two crankshaft revolutions. Within a working cycle, the overlap area 49 is situated, with respect to the crankshaft angle 44 in degrees, after the maximum lifts of the exhaust valve actuation curve 41. Within a working cycle, the overlap area is situated, with respect to the crankshaft angle 44 in degrees, between the smaller maximum lift of the exhaust valve actuation curve 41 and the maximum lift of the intake valve actuation curve 37. Within a working cycle, the overlap area 49 is situated, with respect to the crankshaft angle 44 in degrees, between the zero lift 45 and the intake valve opening point 47; within a working cycle the zero lift 45 is situated, with respect to the crankshaft angle 44 in degrees, before the intake valve opening point 47.

The intake valve actuation curve 37, the exhaust valve actuation curve 41, and the piston lift curve 46 are plotted in a diagram illustrated in FIG. 2, the crankshaft angle 44 in degrees being plotted on the x axis of the diagram, and the lift being plotted on the y axis of the diagram. In principle, the internal combustion engine valve train device may also have a different number of intake cams, intake cam elements, exhaust cams, and/or exhaust cam elements which appear to be meaningful to those skilled in the art.

For setting the normal mode and the exhaust gas recirculation mode, the operating mode switching unit 12 switches between the different intake valve actuation curves of the intake valve actuating unit 11 and the different exhaust valve actuation curves of the exhaust valve actuating unit 10. The operating mode switching unit 12 has a switch gate 31 for switching the intake valve actuating unit 11, and a switch gate 32 for switching the exhaust valve actuating unit 10. The switch gate 31 is situated on the intake cam element 38 in a rotationally and displaceably fixed manner, and the switch gate 32 is situated on the exhaust cam element 42 in a rotationally and displaceably fixed manner. For switching the normal mode and the exhaust gas recirculation mode, the switch gate 31 converts a rotary movement 33 of the intake cam element 38 into an axial movement 35 of the intake cam element 38 along the intake cam base shaft 39. For switching the normal mode and the exhaust gas recirculation mode, the switch gate 32 converts a rotary movement 34 of the exhaust cam element 42 into an axial movement 36 of the exhaust cam element 42 along the exhaust cam base shaft 43. The switch gates 31, 32 have a gate track 50, 51, respectively. In principle, the switch gate 31 may be formed in one piece with the intake cam element 38, as a result of which the intake cam element 38 includes the gate track 50. Additionally or alternatively, the switch gate 32 may be formed in one piece with the exhaust cam element 42, as a result of which the exhaust cam element 42 includes the gate track 51.

The operating mode switching unit 12 also has an actuating unit 52 for switching the intake valve actuating unit 11, and an actuating unit 53 for switching the exhaust valve actuating unit 10. The actuating units 52, 53 each have a switch pin, not illustrated, which for switching extends and engages with the corresponding gate track 50, 51, thus converting the corresponding rotary movement 33, 34 into the corresponding axial movement 35, 36, and thus switching the normal mode or the exhaust gas recirculation mode. The operating mode switching unit 12 is designed as a valve lift switching unit.

For controlling or regulating the switching, the operating mode switching unit 12 has a control and regulation unit, not illustrated, which is in communicating connection with the actuating units 52, 53. The control and regulation unit controls or regulates the extension of the switch pins. For adjusting the internal exhaust gas recirculation, the control and regulation unit switches the exhaust valve actuating unit 10 and also the intake valve actuating unit 11 into the exhaust gas recirculation mode. For setting the normal mode, the control and regulation unit switches the exhaust valve actuating unit 10 and also the intake valve actuating unit 11 into the normal mode.

The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof

LIST OF REFERENCE NUMERALS

10 Exhaust valve actuating unit

11 Intake valve actuating unit

12 Operating mode switching unit

13 Intake cam

14 Intake cam

17 Cam track

18 Cam track

19 Valve actuation parameter

20 Valve actuation parameter

21 Intake valve opening phase

22 Exhaust valve opening phase

23 Exhaust valve opening phase

24 Exhaust cam

25 Exhaust cam

28 Cam track

29 Valve actuation parameter

30 Valve actuation parameter

31 Switch gate

32 Switch gate

33 Rotary movement

34 Rotary movement

35 Axial movement

36 Axial movement

37 Intake valve actuation curve

38 Intake cam element

39 Intake cam base shaft

40 Cam track

41 Exhaust valve actuation curve

42 Exhaust cam element

43 Exhaust cam base shaft

44 Crankshaft angle

45 Zero lift

46 Piston lift curve

47 Intake valve opening point

48 Intake valve closing point

49 Overlap area

50 Gate track

51 Gate track

52 Actuating unit

53 Actuating unit 

1-11. (canceled)
 12. An internal combustion engine valve train device of a motor vehicle, comprising: at least one exhaust valve actuating unit; at least one intake valve actuating unit; and an operating mode switching unit structurally configured to switch the exhaust valve actuating unit into an exhaust gas recirculation mode to adjust an internal exhaust gas recirculation, the intake valve actuating unit into an exhaust gas recirculation mode in order to adjust an internal exhaust gas recirculation, wherein the intake valve actuating unit has at least one intake cam which includes at least one first cam track for a normal mode and a second cam track for the exhaust gas recirculation mode.
 13. The internal combustion engine valve train device of claim 12, wherein the second cam track of the at least one intake cam differs from the at least one first cam track of the at least one intake cam by at least one valve actuation parameter.
 14. The internal combustion engine valve train device of claim 12, wherein the second cam track of the at least one intake cam is configured to set an intake valve opening phase at least essentially outside an exhaust valve opening phase.
 15. The internal combustion engine valve train device of claim 12, wherein the second cam track of the at least one intake cam provides a valve actuation parameter as a lift height that differs from a lift height of the first cam track of the at least one intake cam.
 16. The internal combustion engine valve train device of claim 15, wherein the lift height of the second cam track of the at least one intake cam is smaller than the lift height of the first cam track of the at least one intake cam.
 17. The internal combustion engine valve train device of claim 12, wherein the second cam track of the at least one intake cam provides a valve actuation parameter that is an opening duration and that differs from an opening duration of the first cam track of the at least one intake cam.
 18. The internal combustion engine valve train device of claim 17, wherein the opening duration of the second cam track of the at least one intake cam, is shorter than the opening duration of the first cam track of the at least one intake cam.
 19. The internal combustion engine valve train device of claim 12, wherein the exhaust valve actuating unit has at least one exhaust cam, with at least one cam track for the exhaust gas recirculation mode that provides at least two valve actuation parameters for a lift height that differ from a lift height of the second cam track of the at least one intake cam.
 20. The internal combustion engine valve train device of claim 19, wherein the lift height of the second cam track of the at least one intake cam is smaller than at least one of the two valve actuation parameters of the cam track of the at least one exhaust cam.
 21. The internal combustion engine valve train device of claim 12, wherein the operating mode switching unit has at least one switch gate configured to convert a rotary movement into an axial movement, at least for switching the exhaust gas recirculation mode. 